A number of papers have been presented that define the critical buckling force in inclined straight holes. This paper presents a method for calculating the critical buckling force in vertically and laterally curved and inclined boreholes.

The paper includes methods for computing the bending stress of buckled pipe with tool joints. It also includes a method for computing if the deflection of the pipe at midspan will cause the pipe body to touch the wall of the hole. This approach resolves the question of how tool joints affect the critical buckling force, the curvature of the pipe, and maximum bending stresses.

The paper includes plots of the critical buckling force versus hole curvature for common sizes of drillpipe and Heviwate. We also include plots of the maximum bending stress versus axial force and hole curvature for several sizes of drillpipe and Heviwate.

You can access this article if you purchase or spend a download.